Artificial limb and the like



To all whom it ma PATENT OFFICE.

.TuLIus ALWIN LoTH, or

UTRECHT, NETHERLANDS.

ARTIFICIAL HMB AND THE LIKE.

' Application mea may 7,

concern.' j

Be it known that JULIUs ALWIN Lo'rH, manufacturer of chirurgical instruments, a subject of the Queen of the Netherlands, and residing at Utrecht, Netherlands, have invented certain new and useful Improvements in or Relating to Artificial Limbs and the like, of which the following is a specicatlon.

As is well known, natural `knee and elbow joints are not simple hinged joints, but the ends of the upper` and lower bones of the arm and leg roll on one another, the shape of the rolling faces being such that the arm or leg is shortened or lengthened when bending or straightenin them, respectively. Consequently artificial Iimbs that comprise pivotally connected parts for clasping the upper and lower parts of the arm or leg have the defect `that when bending and straighteningthem `the stump has `to move axially in the casing surrounding it; because the artificial limb maintains its length while the natural lower part of the limb moves axially relatively to the upper part of the limb. j j

Joints for orthopedic knee-stretching devices are known intended to imitate the movement of the natural joint by means of 30 a curved guide. These joints, however, could not heretofore be used for making ar tiiicial limbs, because their lower part does not move axiallyrelatively to the upper part and the construction was not suitable, particularly, the pins wore quicklyin their gixiides and broke, and also the `friction in t e joints was too great.

A primary object of my invention is to provide an improved joint to which these defects are not attached, so that it is `adapted for use in artificial arms and legs and in medico-mechanical apparatus for moving stiff knees and elbows. I attain this end by using two guiding grooves the one of which corresponds in shape to that of the rolling face of the natural bone and the other being inclined against the axis of the limb in such a manner that during the bending of the joint the actual center of rotation moves to the rear side of the part bearing said inclined groove and balls for connecting the two parts of the joint, the one half of each ball running in the one part, and the other half in the other part of the joint.

Specification of Letters Patent.

Patented sept. 1s, 1921.

1918. Serial No. 233,066.

To this and other ends my invention consists of the construction, arrangement and combination of parts described hereinafter and pointed out inthe claims.

Several embodiments of my invention are diagrammatically represented by way of example in the accompanying drawings, wherein Fi ures l and 2 are side elevations showing t e jointin two different positions, the `front part of the joint having been removed,

Fig. 3 iS a vertical section of the joint as shown in Fig. l, and

Fig. 4 is a diagram showing the action of a natural `knee joint;

Fig. ,5, is a modified form of a cording to my invention.

Referring to the drawing, the bar a is for attachment to the uiper part `of the artificial arm or leg, `whi e the bar Z) is for con nection with the lower part of the artificial arm or leg. In the embodiment of the bar b is made fork-shaped by means of a cap c (Fig. 3), this being removed in Figs. l and 2. The bar a has in one or, as shown, in both sides a curved groove Z which correspends in shape to that of the rolling face o (Fig. fi) of the bone ofthe natural arm or leg. A ball e runs in this groove d, approximately half of it being located in this curved groove and the other half in a recess f in the bar I) of the lower part of the leg or arm. The second ball ,f/ is half ina recess It in the bar a` and halt in a groove a' in the bar b, said groove being inclined against the axis of the bar b. If a cap Vc is employed, as shown in the drawing, its side facing the bar o is formed correspondingly, so that the guidance is the same on both sides. In the extended position shown in Fig. 1 the ball g is located close to the extreme end of the groove e, and the ball e is located near the lower end of the curve d remote from the center of the joint. IVhen bending the joint (Fig. 2), the ball e rolls joint acin the groove l and arrives into the part of p prothesis was heretofore sitions relatively to the upper part Vm', shows that the movement corresponds exactly to that of the natural joint.

My improved joint is particularly adapted for use in artificial limbs for attachment to short stumps below. the knee capable or" carrying loads. lThe construction of such particularly diiicult because, as mentioned above, when the leg was being bent the stump moved axially and was consequently lifted from its seat, so that could not be used for carrying` a load. In this case only the protuberance of the thigh or seat bone could be used. When the improved joint is employed the stump always remains in place on its seat and, consequently, when capable ofcarrying a load can be used for thisV purpose. y ForV preventing the knee or elbow being bent through too large an angle a stop 1L is provided on the part Zisliding in a groove or slot al of the part a.

Iln the embodiment (Figs. l-3) the groove d is in the part a and the grooves z' in the parts b and c. ,Of course the reverse arrangement may be obtained if desired, asA

shown in Fig. 5.

Having described my invention, I claim and desire to secure by Letters Patent.

l. In a joint of the character described for artificial -limbs the combination of two parts guided against each other by two guiding grooves the one of which corresponding in Vshape to that of the rolling face of the natural bone and the other being inclined against the axis of the limb in such a manner that during the bending of the joint the actual center of rotation moves to the rear lside'of the part bearing said inclined groove,

and means for holding the two parts together.

2. In a joint of the character described for artificial limbs, the combination of two parts each being provided with a recess and a guiding groove, the ene ofy said guiding grooves corresponding in shape to that of the rolling face of the natural bone and the other being inclined against the axis of the limb in such a manner that during the bending of the joint the actual center of rotation moves to the rear side of the part bearing said inclined groove, balls located approximately halt in a recess in one part and on a groove in the other part and means for holding the two parts and the balls together.

3. In a joint of the character described for artificial limbs, the combination of a joint part to be attached to the upper part of the artificial limb, a second joint part to be attached to the lower part of the artilicial limb, the two joint parts being guided against each other by guiding grooves, one of said grooves being provided in each of the said joint parts, the groove of the first named joint part corresponding in shape to that of the rolling face oi' the natural bone and the groove of the second named joint part being inclined against the axis or' the lower part of the artificial limb in such a manner that during the bending or" the joint the said lower part is raised against the said upper part of the artificial limb, and means for holding the two parts together.

4. In a joint of the character described for artiicial limbs, the combination of one part having a recess and a groove in opposite faces, a forked second part embracing the recessed grooved portion of the former part and having grooves and recesses on the faces adjacent thereto, the grooves in the one part corresponding in shape to that of the rolling face of the natural bone and the grooves on the other part being inclined against the axis of the limb in such a manner that during the bending of the joint the actual center of rotation moves to the rear side ofthe part bearing said inclined groove, balls located approximately half` in a recess in one part and in a grooife in the other part and means for holding the two parts and the balls together.

In testimony whereof I have aflixed my signature.

IULIUS ALWIN LOTH. 

